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| United States Patent |
5,011,902
|
|
Foucht
|
April 30, 1991
|
Co-catalyst system for preparing polyurethane based plywood-patch
compositions
Abstract
A plywood-patching composition is provided based on a non-cellular
polyurethane elastomer prepared by reacting a polyether or polyester
polyol with a polyisocyanate in the presence of a catalytic amount of a
co-catalyst system comprising an organo-bismuth compound, preferably a
bismuth salt of a carboxylic acid, and at least one organo-metallic
compound, preferably a metal salt of a carboxylic acid, wherein the metal
is selected from the group consisting of zinc, antimony and lithium and
wherein the bismuth and metal are present in an effective mole ratio; and
process for preparing same. The catalysts utilized are relatively
non-toxic, yet they promote rapid polymerization with essentially no
foaming for a wide variety of non-cellular polyurethane elastomeric
applications, particularly in plywood-patch applications where even small
amounts of foaming are deleterious to the properties thereof.
| Inventors:
|
Foucht; Millard E. (Stone Mountain, GA)
|
| Assignee:
|
Georgia-Pacific Resins, Inc. (Atlanta, GA)
|
| Appl. No.:
|
430048 |
| Filed:
|
November 1, 1989 |
| Current U.S. Class: |
528/55; 502/102; 502/170; 528/57 |
| Intern'l Class: |
C08G 018/22 |
| Field of Search: |
528/55,57
502/102,170
|
References Cited
U.S. Patent Documents
| 1878962 | Sep., 1932 | Meidert | 528/57.
|
| 3164557 | Jan., 1965 | Merten et al. | 528/57.
|
| 3203932 | Aug., 1965 | Frisch et al. | 528/55.
|
| 3245957 | Apr., 1966 | Hindersinn et al. | 528/57.
|
| 3245958 | Apr., 1966 | Hindersinn et al. | 528/55.
|
| 3407153 | Oct., 1968 | Bowman et al. | 528/55.
|
| 3450653 | Jun., 1969 | McCellan et al. | 528/57.
|
| 3583945 | Jun., 1971 | Robins | 528/57.
|
| 3592787 | Jul., 1971 | Robins | 528/55.
|
| 3691135 | Sep., 1972 | Schulze et al. | 528/55.
|
| 3714077 | Jan., 1973 | Cobbledick et al. | 528/57.
|
| 3725355 | Apr., 1973 | Parrish et al. | 528/55.
|
| 3799898 | Mar., 1974 | Lamplugh et al. | 528/55.
|
| 3801532 | Apr., 1974 | Olstowski | 528/57.
|
| 3901852 | Aug., 1975 | Shah | 528/57.
|
| 3912516 | Oct., 1975 | Recchia et al. | 528/57.
|
| 3929732 | Dec., 1975 | Shah | 528/57.
|
| 3957753 | May., 1976 | Hostettler et al. | 528/55.
|
| 4000103 | Dec., 1976 | Olstowski | 528/55.
|
| 4000104 | Dec., 1976 | Olstowski | 528/57.
|
| 4001165 | Jan., 1977 | Olstowski | 528/55.
|
| 4067844 | Jan., 1978 | Barron et al. | 528/55.
|
| 4115301 | Sep., 1978 | Kennedy | 528/57.
|
| 4189541 | Feb., 1980 | Ohashi et al. | 528/55.
|
| 4284751 | Aug., 1981 | Hutt et al. | 528/55.
|
| 4296172 | Oct., 1981 | Hill | 528/55.
|
| 4306052 | Dec., 1981 | Bonk et al. | 528/57.
|
| 4321333 | Mar., 1982 | Alberino et al. | 528/57.
|
| 4349663 | Sep., 1982 | Barsa et al. | 528/57.
|
| 4374210 | Feb., 1983 | Ewen et al. | 528/55.
|
| 4385133 | May., 1983 | Alberino et al. | 528/57.
|
| 4410689 | Oct., 1983 | Barsa et al. | 528/55.
|
| 4412033 | Oct., 1983 | LaBelle et al. | 528/55.
|
| 4426485 | Jan., 1984 | Hoy et al. | 528/57.
|
| 4448816 | May., 1984 | Barsa et al. | 528/57.
|
| 4452829 | Jun., 1984 | Smith | 528/55.
|
| 4468478 | Aug., 1984 | Dexheimer et al. | 528/55.
|
| 4497913 | Feb., 1985 | Raes et al. | 528/55.
|
| 4584362 | Apr., 1986 | Leckart et al. | 528/57.
|
| Foreign Patent Documents |
| 40469 | Nov., 1981 | EP.
| |
| 2309535 | Aug., 1974 | DE.
| |
| 1294010 | Apr., 1962 | FR.
| |
| 1317150 | Dec., 1962 | FR.
| |
| 994348 | Jun., 1965 | GB.
| |
| 1107480 | Mar., 1968 | GB.
| |
Other References
J. W. Britain et al., "Catalysis of the Isocyanate-Hydroxyl Reaction",
Journal of Applied Polymer Science IV, pp. 207-211, (1960).
N. Irving Sax, "Dangerous Properties of Industrial Materials", Sixth
Edition, p. 496, (1984).
The Merck Index, 10th Edition, p. 178, (1983).
J. D. Arenivar, "Bismuth Carboxlates for Polyurethane Catalysts", 32nd
Annual Polyurethane Technical/Marketing Conference, pp. 623-627, Oct. 1-4,
1989.
A. R. Leckart et al., "New Catalyst for Two-Component Elastomer Systems",
found in Journal of Elasters and Plastics, vol. 19-Oct. 1987, pp. 313-324.
Dabco, K-15 and T-45 Catalyst from Air Products and Chemicals, Inc.,
"Product Bulletins" & MSD Sheet for K-15.
Fomrez EC-683, EC-686, and EC-688 available from WITCO Chemical
Corporation, "Product Bulletins".
|
Primary Examiner: Welsh; Maurice J.
Claims
I claim:
1. A process for preparing a polyurethane elastomer consisting essentially
of the step of reacting a polyol selected from polyether polyols and
polyester polyols with an organic polyisocyanate wherein the ratio of NCO
groups to hydroxyl groups is greater than about 1.00 to 1 in the presence
of a catalytic amount of a co-catalyst system, said co-catalyst system
consisting essentially of an organo-bismuth compound and at least one
organo-metallic compound, wherein said at least one organo-metallic
compound contains a metal selected from the group consisting of zinc,
antimony, lithium and combinations thereof and wherein the bismuth
contained in said organo-bismuth compound and said metal contained in said
organo-metallic compound are present in an effective mole ratio of bismuth
to said metal, with the proviso that if said metal is zinc then said
effective mole ratio is from about 1:4 to about 1:1, with the proviso that
if said metal is antimony then said effective mole ratio is from about
1:1.1 to about 1:0.4, and with the proviso that if said metal is lithium
then said effective mole ratio is from about 1:6.6 to less than about
1:1.6.
2. The process according to claim 1, wherein said organo-bismuth compound
is a bismuth salt of a first carboxylic acid having from 2 to about 20
carbon atoms in the molecule.
3. The process according to claim 2, wherein said organo-metallic compound
is a metal salt of a second carboxylic acid having from 2 to about 20
carbon atoms in the molecule.
4. The process according to claim 1, wherein the metal is zinc.
5. The process according to claim 4, wherein the mole ratio of bismuth to
zinc is from about 1:4 to about 1:1.
6. The process according to claim 1, wherein the metal is antimony.
7. The process according to claim 6, wherein the mole ratio of bismuth to
antimony is from about 1:1.1 to about 1:0.4.
8. The process according to claim 1, wherein the metal is lithium.
9. The process according to claim 8, wherein the mole ratio of bismuth to
lithium is from about 1:6.6 to less than about 1:1.6.
10. The process according to claim 1 wherein the polyol has a molecular
weight of about 1,000 to about 10,000.
11. The process according to claim 1 wherein the reaction is performed in
the presence of about 0.1 to about 3% w, based on the weight of the
reactants, of said co-catalyst system.
12. A process for preparing a polyurethane elastomer consisting essentially
of the step of reacting a polyol selected from polyether polyols and
polyester polyols with an organic polyisocyanate, in the presence of an
effective amount of a chain extender, wherein the ratio of NCO groups to
hydroxyl groups is greater than about 1.00 to 1 in the presence of a
catalytic amount of a co-catalyst system, said co-catalyst system
consisting essentially of an organo-bismuth compound and at least one
organo-metallic compound, wherein said at least one organo-metallic
compound contains a metal selected from the group consisting of zinc,
antimony, lithium and combinations thereof and wherein the bismuth
contained in said organo-bismuth compound and said metal contained in said
organo-metallic compound are present in an effective mole ratio of bismuth
to said metal, with the proviso that if said metal is zinc then said
effective mole ratio is from about 1:4 to about 1:1, with the proviso that
if said metal is antimony then said effective mole ratio is from about
1:1.1 to about 1:0.4, and with the proviso that if said metal is lithium
then said effective mole ratio is from about 1:6.6 to less than about
1:1.6.
13. The process according to claim 12, wherein said organo-bismuth compound
is a bismuth salt of a first carboxylic acid having from 2 to about 20
carbon atoms in the molecule.
14. The process according to claim 13, wherein said organo-metallic
compound is a metal salt of a second carboxylic acid having from 2 to
about 20 carbon atoms in the molecule.
15. The process according to claim 12, wherein the metal is zinc.
16. The process according to claim 15, wherein the mole ratio of bismuth to
zinc is from about 1:4 to about 1:1.
17. The process according to claim 12, wherein the metal is antimony.
18. The process according to claim 17, wherein the mole ratio of bismuth to
antimony is from about 1:1.1 to about 1:0.4.
19. The process according to claim 12, wherein the metal is lithium.
20. The process according to claim 19, wherein the mole ratio of bismuth to
lithium is from about 1:6.6 to less than about 1:1.6.
21. The process according to claim 12 wherein the polyol has a molecular
weight of about 1,000 to about 10,000.
22. The process according to claim 12 wherein the reaction is performed in
the presence of about 0.1 to about 3% w, based on the weight of the
reactants, of said co-catalyst system and from about 1% w to about 20% w
based on the weight of the reactants of a chain extender.
23. A plywood-patch composition based on a non-cellular polyurethane
elastomer, said plywood-patch composition comprising the reaction product
of a Component A and a Component B in the presence of a catalytic amount
of a co-catalyst system,
wherein said Component A comprises
(a) from about 15 to about 40% w of a poly(oxyalkylene) polyol having at
least three (3) hydroxyl groups,
(b) from 0 to about 16% w of a poly(oxyalkylene)diol,
(c) from 0 to about 2.5% w of a compatibilizer for said Component A and
said Component B,
(d) from 0% w to about 12% w of a non-reactive diluent for said Component
A,
(e) from 0 to about 2% w of a desiccant,
(f) from 0 to about 1% w of a thixotrope,
(g) from about 30 to about 70% w of a filler,
(h) from 0 to about 2% w of a pigment, and
(i) from 0 to about 2% w of an anti-settling agent,
wherein % w is based on Component A,
wherein Component B is an organic polyisocyanate,
wherein the ratio of NCO groups to hydroxyl groups is greater than about
1.00 to 1 and
wherein said co-catalyst system consists essentially of an organo-bismuth
compound and at least one organo-metallic compound, wherein said at least
one organo-metallic compound contains a metal selected from the group
consisting of zinc, antimony and lithium and wherein the bismuth contained
in said organo-bismuth compound and said metal contained in said
organo-metallic compound are present in an effective mole ratio of bismuth
to said metal, with the proviso that if said metal is zinc then said
effective mole ratio is from about 1:4 to about 1:1, with the proviso that
if said metal is antimony then said effective mole ratio is from about
1:1.1 to about 1:0.4, and with the proviso that if said metal is lithium
then said effective mole ratio is from about 1:6.6 to less than about
1:1.6.
24. The composition according to claim 23, wherein said organo-bismuth
compound is a bismuth salt of a first carboxylic acid having from 2 to
about 20 carbon atoms in the molecule.
25. The composition according to claim 24, wherein said organo-metallic
compound is a metal salt of a second carboxylic acid having from 2 to
about 20 carbon atoms in the molecule.
26. The composition according to claim 23, wherein the metal is zinc.
27. The composition according to claim 26, wherein the mole ratio of
bismuth to zinc is from about 1:4 to about 1:1.
28. The composition according to claim 23, wherein the metal is antimony.
29. The composition according to claim 28, wherein the mole ratio of
bismuth to antimony is from about 1:1.1 to about 1:0.4.
30. The composition according to claim 23, wherein the metal is lithium.
31. The composition according to claim 30, wherein the mole ratio of
bismuth to lithium is from about 1:6.6 to less than about 1:1.6.
32. The plywood-patch composition according to claim 23 wherein the
poly(oxyalkylene) polyol having at least three (3) hydroxyl groups is a
mixture of a first and a second poly(oxyalkylene)triol, wherein said first
poly(oxyalkylene)triol is present from about 15 to about 30% w and has a
molecular weight from about 1,000 to less than 3,000 and a hydroxyl number
from about 60 to about 150 and wherein said second poly(oxyalkylene)triol
is present from about 5 to about 15% w and has a molecular weight from
about 3,000 to about 10,000 and a hydroxyl number from about 30 to about
100.
33. The plywood-patch composition according to claim 23 wherein the
poly(oxyalkylene) polyol having at least three (3) hydroxyl groups is a
poly(oxyalkylene)triol and is present from about 15 to about 30% w and has
a molecular weight of from about 1,000 to about 5,000 and a hydroxyl
number from about 60 to about 150 and wherein the poly(oxyalkylene)diol is
present from about 5% to about 15% w and has a molecular weight of between
1,000 and about 5,000 and a hydroxyl number from about 30 to about 100.
34. A process for preparing a plywood-patch composition based on a
non-cellular polyurethane elastomer consisting essentially of the step of
reacting a Component A and a Component B in the presence of a catalytic
amount of a co-catalyst system, wherein said Component A is prepared by
mixing
(a) from about 15 to about 40% w of a poly(oxyalkylene)polyol having at
least three hydroxyl groups,
(b) from 0 to about 16% w of a poly(oxyalkylene)diol,
(c) from 0 to about 2.5% w of a compatibilizer for said Component A and
said Component B,
(d) from 0 to about 12% w of a non-reactive diluent for said Component A,
(e) from 0 to about 2% w of a desiccant,
(f) from 0 to about 1% w of a thixotrope,
(g) from about 30 to about 70% w of a filler,
(h) from 0 to about 2% w of a pigment, and
(i) from 0 to about 2% w of an anti-settling agent,
wherein % w is based on Component A,
wherein Component B is an organic polyisocyanate,
wherein the ratio of NCO groups to hydroxyl groups is greater than about
1.00 to 1 and
wherein said co-catalyst system consists essentially of an organo-bismuth
compound and at least one organo-metallic compound, wherein said at least
one organo-metallic compound contains a metal selected from the group
consisting of zinc, antimony and lithium and wherein the bismuth contained
in said organo-bismuth compound and said metal contained in said
organo-metallic compound are present in an effective mole ratio of bismuth
to said metal, with the proviso that if said metal is zinc then said
effective mole ratio is from about 1:4 to about 1:1, with the proviso that
if said metal is antimony then said effective mole ratio is from about
1:1.1 to about 1:0.4, and with the proviso that if said metal is lithium
then said effective mole ratio is from about 1:6.6 to less than about
1:1.6.
35. The process according to claim 34, wherein said organo-bismuth compound
is a bismuth salt of a first carboxylic acid having from 2 to about 20
carbon atoms in the molecule.
36. The process according to claim 35, wherein said organo-metallic
compound is a metal salt of a second carboxylic acid having from 2 to
about 20 carbon atoms in the molecule.
37. The process according to claim 34, wherein the metal is zinc.
38. The process according to claim 37, wherein the mole ratio of bismuth to
zinc is from about 1:4 to about 1:1.
39. The process according to claim 34, wherein the metal is antimony.
40. The process according to claim 39, wherein the mole ratio of bismuth to
antimony is from about 1:1.1 to about 1:0.4.
41. The process according to claim 34, wherein the metal is lithium.
42. The process according to claim 41, wherein the mole ratio of bismuth to
lithium is from about 1:6.6 to less than about 1:1.6.
43. The process according to claim 34 wherein the poly(oxyalkylene) polyol
having at least three (3) hydroxyl groups is a mixture of a first and a
second poly(oxyalkylene)triol, wherein the first poly(oxyalkylene)triol is
present from about 15 to about 30% w and has a molecular weight from about
1,000 to less than 3,000 and a hydroxyl number from about 60 to about 150
and wherein the second poly(oxyalkylene)triol is present from about 5 to
about 15% w and has molecular weight from about 3,000 to about 10,000 and
a hydroxyl number from about 30 to about 100.
44. The process according to claim 34 wherein the poly(oxyalkylene) polyol
having at least three (3) hydroxyl groups is a poly(oxyalkylene)triol and
is present from about 15 to about 30% w and has a molecular weight from
about 1,000 to about 5,000 and a hydroxyl number from about 60 to about
150 and wherein the poly(oxyalkylene)diol is present from about 5 to about
15% w and has a molecular weight from about 1,000 to about 5,000 and a
hydroxyl number from about 30 to about 100.
45. A co-catalyst system for preparing a polyurethane elastomer from a
polyol selected from polyether polyols and polyester polyols and an
organic polyisocyanate, said co-catalyst system consisting essentially of
an organo-bismuth compound and at least one organo-metallic compound,
wherein said at least one organo-metallic compound contains a metal
selected from the group consisting of zinc, antimony, lithium and
combinations thereof and wherein the bismuth contained in said
organo-bismuth compound and said metal contained in said organo-metallic
compound are present in an effective mole ratio of bismuth to said metal,
with the proviso that if said metal is zinc then said effective mole ratio
is from about 1:4 to about 1:1, with the proviso that if said metal is
antimony then said effective mole ratio is from about 1:1.1 to about 1:0.4
and with the proviso that if said metal is lithium then said effective
mole ratio is from about 1:6.6 to less than about 1:1.6.
46. The co-catalyst system according to claim 45, wherein said
organo-bismuth compound is a bismuth salt of a first carboxylic acid
having from 2 to about 20 carbon atoms in the molecule.
47. The co-catalyst system according to claim 46, wherein said
organo-metallic compound is a metal salt of a second carboxylic acid
having from 2 to about 20 carbon atoms in the molecule.
48. The co-catalyst system according to claim 1, wherein the metal is zinc.
49. The co-catalyst system according to claim 45, wherein the metal is
antimony.
50. The co-catalyst system according to claim 45, wherein the metal is
lithium.
Description
FIELD OF THE INVENTION
This invention relates to polyurethanes and more particularly it relates to
non-cellular polyurethanes prepared utilizing a catalytic amount of a
co-catalyst system comprising an organo-bismuth compound, preferably a
bismuth salt of a carboxylic acid, and at least one organo-metallic
compound, preferably a metal salt of a carboxylic acid, wherein the metal
is selected from the group consisting of zinc, antimony and lithium and
wherein the bismuth and metal are present in an effective mole ratio, such
polyurethanes being particularly useful in plywood-patch compositions.
BACKGROUND OF THE INVENTION
Urethane polymers or polyurethanes are a large family of polymers with
widely varying properties and uses, all based on the reaction product of
an organic isocyanate with compounds containing a group with an active
hydrogen, such as a hydroxyl group. Polyurethane polymers are generally
classified into two broad categories. A. foam or urethane foam, and B.
elastomers or polyurethane elastomers. Polyurethane foams are polyurethane
polymers produced by the reaction of polyisocyanates with a hydroxyl group
from a polyol and a polymerization catalyst, in the presence of water
and/or an auxiliary blowing agent, such as monofluorotrichloromethane,
which allows the polymeric mass to expand into a cellular mass upon
reaction. In preparing a non-cellular polyurethane elastomer, no blowing
agent or mechanism for producing gas which would lead to cell development
should be present. Therefore, the polymer is produced by the reaction of
the isocyanate with a hydroxyl group to form urethane linkages in the
presence of a polymerization catalyst.
Polyurethane elastomers have been widely used in a variety of applications.
They have been used as protective coatings, in the insulation of
electrical elements, as caulks, sealants, gaskets, etc. Because of
favorable rheology of an elastomer formulation, they can be used to cast
intricate forms such as found in the toy industry. They have also been
widely used in the preparation of sporting goods, fabric coatings and shoe
soles wherein the cured urethane elastomer comes in repeated intimate
contact with human beings. The prior art catalysts used to prepare
non-cellular elastomers frequently contained toxic mercury and lead
compounds and the toxicity was carried over into the cured elastomer. If
less toxic organo-tin compounds are employed as catalysts, elastomers
having physical properties less than optimum are often obtained.
There are several patents relating to various catalysts for reacting
isocyanates with polyether polyols. U.S. Pat. No. 3,245,957 to Hendersinn
et al. describes a process for reacting an isocyanate with an active
hydrogen compound in the presence of an antimony containing catalyst.
U.S. Pat. No. 3,203,932 to Frisch et al. relates to a process for preparing
urethane-urea elastomers using metal organic catalysts such as lead,
cobalt and zinc naphthenates.
U.S. Pat. No. 4,468,478 to Dexheimer et al. discloses polyurethanes
prepared from polyoxyalkylenes containing alkali metal or alkaline earth
metal catalyst residues chelated with benzoic acid derivatives.
U.S. Pat. No. 3,714,077 to Cobbledick et al. relates to a urethane foam
catalyst system consisting of a combination of polyol-soluble organic
stannous compounds with polyol-soluble organic bismuth and/or antimony
compounds with certain sterically hindered tertiary amines.
U.S. Pat. Nos. 3,801,532, 4,000,103, 4,000,104 and 4,001,165 to Olstowski
disclose rapid-setting polyurethanes prepared from diols and
polyfunctional isocyanates using organo-metal compounds of tin, zinc,
lead, mercury, cadmium, bismuth, cobalt, manganese, antimony and iron,
such as stannous octoate, manganese octoate, lead octoate, and dibutyl tin
dilaurate.
U.S. Pat. No. 4,584,362 to Leckart et al. relates to polyurethane
elastomers prepared utilizing as the sole catalyst therein a bismuth salt
of a carboxylic acid having from 2 to 20 carbon atoms.
U.S. Pat. No. 4,452,829 to Smith discloses a sprayable polyisocyanate
composition prepared by reacting MDI with a triol and a diol utilizing
potassium octoate as a trimerization catalyst and an amine-type
heat-activated catalyst and, optionally, a tetravalent-tin urethane-type
catalyst to provide a solid, coating or foam.
Non-cellular polyurethanes are also used in plywood-patch applications to
fill crevices, voids and other imperfections that occur during the
manufacture of plywood. Polyurethanes are well suited for such
applications because the isocyanates thereof have a natural affinity for
wood. Typically, these compositions are applied in an assembly line
fashion, thereby requiring a rapid cure at room temperature (generally
less than one minute).
Currently, many formulations for this application employ organo-lead
catalysts. However, concern over their toxicity has spurred the search for
effective, non-toxic, alternative catalysts. Organo-mercury catalysts are
too sluggish and are also toxic. Organotins and tertiary amines have a
propensity to react with water causing foam formation which would affect
the adhesion of the patch to the plywood and the mechanical properties,
e.g. hardness, of the patch. As indicated by A. R. Leckart and L. S.
Slovin in their article "New Catalyst for Two-Component Elastomer
Systems," Journal of Elastomers and Plastics, vol. 19, pages 313-324
(1987), organo-bismuth catalysts appear to hold some promise in this
regard, but are about 3 to 5 times more expensive than lead-based
catalysts. Additionally, use of organo-bismuth catalysts in plywood-patch
compositions as a sole catalyst is not desirous due to the fast rate of
gelation achieved which adversely affects the flowability of the precured
composition through the delivery equipment and onto the panel.
Organo-potassium catalysts are a very active species of catalyst, but they
have a great affinity for water (hygroscopic) and also a propensity to
react with water causing foam formation. Additionally, during their
formation, water is produced which is typically not removed due to
handling considerations. When the water of reaction is removed, such
catalysts become too viscous and even become solid as in the case of
potassium octoate, thereby presenting a handling problem. As such,
organo-potassium catalysts are typically relegated to the production of
foams or applications where foaming is not detrimental thereto. However,
there is presently a commercially available plywood-patch composition
which appears to be utilizing a potassium-based catalyst believed to be
potassium octoate. As to be expected, the patch exhibits slight foam
formation due to water contained therein which is sufficient to
significantly impair the properties thereof, particularly adhesion,
hardness and cure time.
SUMMARY OF THE INVENTION
Accordingly, the present invention relates to a plywood-patch composition
based on non-cellular polyurethane elastomers prepared by reacting
polyether or polyester polyols having molecular weights of between about
1000 and about 10,000, optionally in conjunction with a smaller percentage
of lower molecular weight glycols, which provides for a balance of
physical properties required, with an organic polyisocyanate, wherein the
ratio of NCO groups to hydroxyl groups is greater than 1.00 to 1,
preferably from greater than 1.00 to 1 to about 2.0 to 1, in the presence
of a catalytic amount of a co-catalyst system comprising an organo-bismuth
compound, preferably a bismuth salt of a carboxylic acid having from 2 to
about 20 carbon atoms in the molecule, and at least one organo-metallic
compound, preferably a metal salt of a carboxylic acid having from 2 to
about 20 carbon atoms in the molecule, wherein the metal of the
organo-metallic compound is selected from the group consisting of zinc,
antimony, lithium and combinations thereof and wherein the bismuth and
metal are present in an effective mole ratio of bismuth to metal. The
catalytic amount of the co-catalyst system is preferably from about 0.1 to
about 3 percent by weight (% w), more preferably at about 0.2 to about
1.5% w, based on the weight of the polyurethane reactants. The effective
mole ratio of bismuth to zinc is from about 1:4 to about 1:1
(bismuth:zinc). The effective mole ratio of bismuth to antimony is from
about 1:1.1 to about 1:0.4 (bismuth:antimony). The effective mole ratio of
bismuth to lithium is from about 1:6.6 to less than about 1:1.6
(bismuth:lithium). Each of the catalysts in the co-catalyst system may be
dissolved in a suitable solvent forming a catalyst solution prior to
incorporation into the plywood-patch composition or polyurethane elastomer
formulation.
DESCRIPTION OF THE INVENTION
The catalysts utilized in the co-catalyst system of the instant invention
are organo-metallic compounds, for example, metal salts of carboxylic
acids, metal alcoholates, metal phenolates and metal oximes, wherein the
metal is bismuth, zinc, antimony and/or lithium, and may be prepared by
any known method. Metal salts of carboxylic acids are preferred and may be
produced, for example, by reacting a metal-containing base with a
carboxylic acid having 2 to 20 carbon atoms in the molecule, preferably 6
to 16 carbon atoms in the molecule and more preferably 8 to 12 carbon
atoms in the molecule, wherein the metal is bismuth, zinc, antimony and/or
lithium. Useful carboxylic acids are represented by the formula RCOOH
wherein R is a hydrocarbon radical containing 1 to about 19 carbon atoms.
R can be alkyl, cycloalkyl, aryl, or alkylaryl, such as methyl, ethyl,
propyl, isopropyl, neopentyl, octyl, neononyl, cyclohexyl, phenyl, tolyl
or naphthyl. R is preferably alkyl or cycloalkyl, more preferably alkyl.
See for example U.S. Pat. Nos. 4,584,362 (bismuth catalysts); 3,245,958
(antimony catalysts); and 3,714,077 (bismuth and antimony catalysts).
Metal alcoholates are disclosed in U.S. Pat. Nos. 3,245,957 (antimony
catalysts); 3,407,151 (antimony and bismuth catalysts); and 3,714,077
(antimony and bismuth catalysts). The individual catalysts are also
available commercially.
The primary use of the co-catalyst system is to accelerate the reaction
between the isocyanate and the hydroxyl groups. The co-catalyst system can
be employed in a wide range of non-cellular elastomer formulation systems
where reduced catalyst toxicity is desirable, particularly plywood-patch
applications. The co-catalyst system provides an alternative to the use of
catalysts based on lead, tin or mercury with respect to reduced catalyst
toxicity and to the sole use of bismuth-based catalysts with respect to
reduced costs and improved flowability.
Catalysts in use prior to this invention all had the capability of
promoting reaction between a hydroxyl group and isocyanates to produce
urethane linkages and, ultimately, polyurethane products. The major
disadvantage of organo-mercury based catalysts is that, as supplied, they
must be handled with extreme caution due to their classification as
poisons and the shipping containers must be managed under the Resources
Conservation and Recovery Act as hazardous waste. Organo-lead catalysts
must also be handled with a great deal of caution due to their toxicity
classification as a hazardous substance under the Resources Conservation
and Recovery Act. Organo-antimony catalysts must also be handled with
caution due to their toxicity classification as a hazardous chemical by
OSHA. At levels of less than 1 percent by weight antimony, polyurethanes
are considered safe but such levels are not useful for plywood-patch
applications due to slow reactivity. Organo-antimony catalysts also tend
to promote the water/isocyanate reaction.
Primarily due to these considerations of toxicity and handling, the use of
organo-tin catalysts in non-cellular urethane systems has occurred. As a
class, organo-tin compounds do not provide the same type of catalytic
performance as organo-mercury and organo-lead compounds, since organo-tin
compounds also promote the reaction between moisture and isocyanates in
addition to the hydroxy group-isocyanate reaction. The non-specific nature
of the tin catalysts makes their use difficult, with the processor
required to go to extreme measures to reduce the presence of moisture in
the reactants and other ingredients utilized therein in order to eliminate
bubbling or pinhole formation in the elastomers obtained.
In addition, when using catalysts based on mercury, lead or tin, monitoring
of the work place environment must be done in order to ascertain ambient
air quality compliance with Occupational Safety and Health Administration
Standards ("OSHA"). Only general ventilation is required when using
catalysts based on antimony.
The co-catalyst system of this invention provides optimum performance based
on flowability, tailored gel times, adhesion, and hardness in
plywood-patch applications and will not contribute to embrittlement of the
cured elastomer. As a precautionary measure, a desiccant such as molecular
sieve may be added to the formulation in amounts effective for
eliminating, or at least minimizing, any foaming that may occur. Most
importantly, the co-catalyst system has an excellent acute toxicity
profile. No occupational exposure limit standard must be met when using
the co-catalyst system and only general ventilation is required.
It is apparent, therefore, that, when contrasted with organo-mercury
compounds and lead salts of organic acids, the co-catalyst system of this
invention is much less toxic. The toxicity profiles of organo-tin based
chemicals are somewhat poorer, but within about the same order of
magnitude as the compounds of this invention, but when considering their
limitations based on moisture sensitivity and OSHA monitoring
requirements, the safety and ease of use of the compounds of this
invention are evident. The toxicity profiles of organo-bismuth based
chemicals are within about the same order of magnitude as the compounds
utilized herein, but are also about 2 to 4 times more expensive than the
co-catalyst system utilized herein since the organo-bismuth catalyst is
not used as the sole catalyst.
The primary hydroxy containing reactants used in the preparation of the
polyurethane elastomers utilized in the plywood-patch compositions
embodying the present invention are primary and secondary hydroxy
terminated polyalkylene ethers and polyesters having from 2 to about 4
hydroxyl groups and a molecular weight of from about 1000 to about 10,000.
They are liquids or are capable of being liquified or melted for handling.
Examples of polyalkylene polyols include linear and branched polyethers
having a plurality of ether linkages and containing at least 2 hydroxyl
groups and being substantially free from functional groups other than
hydroxyl groups. Typical examples of the polyalkylene polyols which are
useful in the practice of the invention are the polyethylene glycols,
polypropylene glycols and polybutylene ether glycols. Linear and branched
copolyethers of ethylene oxide and propylene oxide are also useful in
preparing the elastomers of this invention. Those having molecular weights
of from about 1000 to about 5000 are preferred. Polyethers having a branch
chain network are also useful. Such branch chain polyethers are readily
prepared from alkylene oxides and initiators having a functionality
greater than 2.
A variety of poly(oxyalkylene) polyols are available commercially with an
exemplary list provided in Table A below:
TABLE A
______________________________________
Avg.
Commercial Prod.
hydroxyl no.
Molecular Wt.
f.sup.a
Mfgr.sup.b
______________________________________
Niax LHT-112
112 1500 3 UCC
Niax LHT-67 67 2000 3 UCC
Niax 11-34 34 4800 3 UCC
Thanol SF-1502
112 1500 3 ARCO
Voranol 2228
28 2715 3 Dow
Voranol 15096.0L
112 1500 3 Dow
XVR 1663-40557-23
110 1500 3 Dow
Voranol 4815
28 6000 3 Dow
Voranol 2140
28 4000 2 Dow
Voranol 2012
94 1200 2 Dow
Voranol 2120
56 2000 2 Dow
Voranol 2100
56 3000 3 Dow
Fomrez X6017-183
140 1600 4 Witco
Fomrez ET 1500
112 1500 3 Witco
Fomrez 6017-133
60 3740 4 Witco
Poly G-30-112
112 1500 3 Olin
Poly G-76-120
110 1500 3 Olin
Poly G-55-56
56 2000 2 Olin
Poly G-20-28
28 4000 2 Olin
Poly G-85-28
27 6500 3 Olin
588-186 60 1870 2 JW
Res-D-2116 82 1370 2 Herc
______________________________________
.sup.a functionality, i.e., number of hydroxyl groups in the polyol, for
example, f = 3 refers to a triol.
.sup.b Manufacturers. The abbreviations correspond to the following
manufacturers:
UCC Union Carbide Corp., Danbury, Connecticut
ARCO ARCO, Newtown Square, Pennsylvania
Dow Dow Chemical Co., Midland, Michigan
Witco Witco Corporation, Chicago, Illinois
Olin Olin Chemicals, Stamford, Connecticut
JW Jim Walters, St. Petersburg, Florida
Herc Hercules, Inc., Wilmington, Delaware
Any organic di or tri isocyanate can be used in the practice of the present
invention. Diisocyanates are preferred. Examples of suitable organic
polyisocyanates are trimethylene diisocyanate, tetramethylene
diisocyanate, pentamethylene diisocyanate and hexamethylene diisocyanate.
Examples of aromatic diisocyanates include 2,4 tolylene diisocyanate, and
2,6 tolylene diisocyanate. In addition, methylene diphenyldiisocyanates
and polymeric isocyanates based on methylene diphenyldiisocyanates can be
employed.
The tolylene diisocyanates (TDI) are monomeric and possess a high vapor
pressure relative to the methylene diisocyanates (MDI), which are
polymeric. The TDI vapors are very toxic and have a propensity of reacting
once in a person's respiratory system. As such, TDI poses a handling
problem and a health hazard. As a result, MDI is preferred for many
applications, including plywood patch material.
The amount of polyisocyanate employed is greater than 1.00, and preferably
ranges from greater than 1.00 to about 2.0, more preferably about 1.05 to
about 1.7, moles of NCO in the polyisocyanate per mole of active hydrogen
in the polyols.
In certain instances it may be desirable to add a chain extender to
complete the formulation of polyurethane polymers by reacting isocyanate
groups of adducts or prepolymers. Examples of some types of polyol chain
extenders include 1,4 butanediol, diethylene glycol, trimethylol propane
and hydroquinone di(beta hydroxyethyl ether).
The chain extender when present is added at about 1% w to about 20% w,
preferably about 3% w to about 6% w based on the weight of the reactants.
Plywood-patch compositions may additionally incorporate diluents, fillers,
compatibilizers, thixotropes, pigments and anti-settling agents. Suitable
fillers include barium sulfate, calcium sulfate, calcium carbonate,
silica, and clay particles, such as aluminum silicates, magnesium
silicates and kaolin. Suitable compatibilizers are hydroxy containing
organic compounds, preferably hydroxy containing monocyclic arenes such as
ethoxylated nonyl phenol, which compatibilize the polyol and aromatic
diisocyanate reactants in the formulation.
Suitable diluents include hydrotreated paraffinic oils, hydrotreated
naphthenic oils, petroleum solvents, aliphatic solvents and propylene
carbonate. An exemplary list of commercial available diluents is given in
Table B below.
TABLE B
______________________________________
Diluent Flash Point (F.)
Manufacturer.sup.a
______________________________________
Propylene carbonate
270 Texaco; ARCO
Hydrotreated
naphthenic oil:
Sunthene 204 265 Sun
Hyprene V-60 300 Ergon
Hydrotreated
paraffinic oil:
Sunpar 107 350 Sun
Sunpar LW104 260 Sun
Sunpar LW003 200 Sun
Aromatic
petroleum solvent:
Aromatic 100 108 Exxon
Hisol-10 110 Ashland
Petroleum Solvent:
Exxsol D110 221 Exxon
Varsol 1 108 Exxon
Varsol 18 106 Exxon
Aliphatic solvents:
PD-23 225 Witco
PD-25 225 Witco
______________________________________
.sup.a The abbreviations correspond to the following:
Texaco Texaco, Inc., Bellaire, Texas
ARCO ARCO, Newtown Square, Pennsylvania
Sun Sun Refining, Philadelphia, Pennsylvania
Exxon Exxon Chemical, Houston, Texas
Ashland Ashland Chemical, Columbus, Ohio
Witco Witco, Sonnaborn Division, NY, New York
Ergon Ergon, Jackson, Mississippi
A preferred plywood-patch composition comprises two components--a component
A and a component B wherein component A ranges from about 6 to about 15
parts to each part of B by volume. Component A comprises (a) from about 15
to about 40% w of a poly(oxyalkylene) polyol having a functionality of at
least 3, preferably a poly(oxyalkylene) triol; (b) from 0 to about 16% w
of poly(oxyalkylene)diol; (c) from 0 to about 2.5% w of a compatibilizer
such as ethoxylated nonyl phenol; (d) from 0 to about 12% w of a
non-reactive diluent; (e) from 0 to about 2% w of a desiccant such as
micronized molecular sieve, preferably 0 to about 1% w; (f) from 0 to
about 0.8% w of a thixotrope, more preferably from 0 to about 0.5% w; (g)
from about 30 to about 70% w of a filler, more preferably from about 50 to
about 65% w; (h) from 0 to about 2% w of a pigment, more preferably from
about 0.05 to about 0.2% w; (i) from 0 to about 2% w of an anti-settling
agent, more preferably from 0 to about 0.5% w; and (j) from about 0.1 to
about 3% w of the co-catalyst system, wherein % w is based on the weight
of Component A. In one embodiment, the poly(oxyalkylene) polyol having at
least three (3) hydroxyl groups is a mixture of a first and a second
poly(oxyalkylene)triol, wherein the first poly(oxyalkylene)triol is
present from about 15 to about 30% w and has a molecular weight from about
1,000 to less than 3,000 and a hydroxyl number from about 60 to about 150
and the second poly(oxyalkylene)triol is present from about 5 to about 15%
w and has a molecular weight from about 3,000 to about 10,000, and a
hydroxyl number from about 30 to about 100, preferably with no
poly(oxyalkylene)diol, wherein % w is based on the weight of Component A.
In another embodiment, the poly(oxyalkylene) polyol having at least three
(3) hydroxyl groups is a poly(oxyalkylene)triol and is present from about
15 to about 30% w and has a molecular weight from about 1,000 to about
5,000 and a hydroxyl number from about 60 to about 150 and a
poly(oxyalkylene)diol is present from about 5 to about 15% w and has a
molecular weight from about 1,000 to about 5,000 and a hydroxyl number
from about 30 to about 100, wherein % w is based on the weight of
Component A.
The component B of the plywood-patch composition is preferably entirely
methylene diphenyl diisocyanate, though mixtures of diisocyanates are also
permissible. Additionally, chain extenders including that amount utilized
as a solvent in the catalyst solution may be present from 0 to about 5% w,
preferably from 0 to about 2% w, based on the weight of Component A. Chain
extenders in excess of these amounts have an adverse affect on adhesion
(American Plywood Association boil test) and hardness (Shore A Durometer
Hardness).
EXAMPLES
The following examples are for illustrative purposes only and are not meant
to limit the claimed invention in any manner. The following tests have
been utilized in some of the examples that follow:
(1) Flowability: The flowability of the chemicals relates to how well the
chemicals process through the mixing/metering equipment and how they flow
to fill surface defects, for example, voids, cracks, knot-holes, splits,
and the like, in the plywood panels. For the mixed chemicals, flowability
relates to two phenomena. First, the initial flowability which is related
to the viscosity of the chemicals initially and which can be measured on a
Brookfield viscometer under high spindle speeds (i.e., the #4 spindle @ 60
rpm's for a model LVF Brookfield). Chemicals of 3000 cps or less will have
good initial flowability for this application. Secondly, as the chemicals
react, the viscosity changes. With an increase in viscosity due to the
crosslinking reaction between the isocyanate and polyol, the flowability
of the chemicals decreases until the gel point is reached, at which time
flow stops. Generally speaking, gel times of 17 to 18 seconds or longer
result in good flowability. Gel times of less than 17 seconds lead to poor
flowability.
(2) Gel time is the point in time from the initial reaction of the
chemicals until the viscosity has increased sufficiently so no flow occurs
or when the polymer has crosslinked sufficiently to form a permanent
shape. The gel time of the chemicals relates to mixing gun tube plugging
and tube replacement costs. The desired gel time is one that is as close
to the tack free time as possible as to maximize flowability.
(3) Tack Free Time is defined as the time from initial mixing until the
surface of the urethane mass loses its stickiness or adhesive quality as
measured by touching the surface with a tongue depressor or one's finger
tip. Tack free time relates to how quickly the plywood patch cures on the
plywood board such that the boards do not stick together during the
stacking operation at the end of the plywood patch operating line.
(4) Shore A durometer hardness test per ASTM D-2240-75, "Rubber
Property-Durometer Hardness". Shore A durometer hardness versus time
relates to how quickly the patch cures on the board so that it resists
damage during stacking, handling, sanding and other plant operations.
(5) Adhesion. A point in time when the urethane mass adheres to the surface
of a plywood panel and cannot be removed by pulling at the edges with
one's fingernail or by thumb pressure. Adhesion is a property that is very
important in terms of the synthetic patch remaining in the filled defect
area as the boards are sanded. The quicker the adhesion times the more
likely the patch will remain in the defect.
In the following examples, the plywood-patch formulation shown in TABLE 1
was utilized, unless otherwise specified. In preparing Component A,
various amounts and types of catalyst and co-catalysts were added to about
100 grams of the base composition shown in TABLE 1 and mixed thoroughly.
Component A was then combined with component B in the proportion of about
10 parts by volume of component A to one part of by volume of component B,
which corresponded to the addition of about 8 grams of MDI. Components A
and B were mixed under high speed agitation for about 10 seconds. The
mixture was then poured onto the surface of an unsanded plywood panel at
about room temperature, about 73.degree. F. Each mixture (sample) was
tested for flowability of the mixture onto the panel, gel time in seconds,
tack free time in seconds, adhesion to the wood surface in seconds, and
the curing hardness profile as measured by Shore A durometer with time as
the variable.
TABLE 1
______________________________________
Plywood-Patch Composition Formulation
______________________________________
Ingredients
Component A:
1. Base composition Percent by Weight
Poly(oxyalkylene) triol.sup.a
18.4
Poly(oxyalkylene) triol.sup.b
13.3
Diluent.sup.c 5.3
Anti-settling agent.sup.d
0.2
Thixotrope.sup.e 0.4
Desiccant.sup.f 1.0
Filler.sup.g 61.3
Pigment.sup.h 0.1
2. Catalyst or catalyst solution
Varied
Component B:
Methylene diphenyl diisocyanate (MDI)
Ratio A to B 10 to 1
(parts by volume):
______________________________________
.sup.a A triol having a molecular weight of about 1500 and hydroxyl numbe
of about 120.
.sup.b A triol having a molecular weight of about 4800 and a hydroxyl
number of about 34.
.sup.c An aromatic petroleum solvent having 100% aromatic content and
having a flash point of about 105.degree. F. and a boiling point of about
308.degree. F.
.sup.d Anti-Terra .RTM. - U80 available from BYK Chemie USA, Wallingford,
Conn. and described as a solution of a salt of unsaturated polyamine amid
and higher molecules of acidic esters.
.sup.e Cab-O-Sil Type M5 available from Cabot Corporation; a fumed silica
.sup.f Molecular Sieve Type 4A is powder form available from Union Carbid
Corporation, Tarrytown, New York, having a nominal pore diameter of about
4 angstroms.
.sup.g Wingdale White available from Georgia Marble Co., Atlanta, Ga., a
calcium carbonate having a mean particle size of about 6 microns.
.sup.h Yellow iron oxide commercially available as Mapico Yellow 1075A
from Columbian Chemicals Co., Atlanta, Ga.
The catalysts or catalyst solutions shown in Table 2 were used in the
following examples:
TABLE 2
______________________________________
Catalyst Code
Description
______________________________________
A Catalyst 320 available from Mooney Chem-
icals, Inc., Cleveland, Ohio, is a catalyst
solution containing about 78% by weight
bismuth 2-ethylhexoate and about 22% by
weight mineral spirits and contains about
28% by weight bismuth.
B 22% Zinc Hex Chem available from
Mooney Chemicals, Inc. is a catalyst com-
posed of 100% zinc octoate (zinc
2-ethylhexoate) and contains about 22% by
weight zinc.
C 18% Antimony Hex Chem available from
Mooney Chemicals, Inc. is a catalyst solu-
tion containing about 98% by weight anti-
mony 2-ethylhexoate and about 2% by
weight mineral spirits and contains about
18% by weight antimony.
D 2% Lithium Ten-Cem HF available from
Mooney Chemicals, Inc., is a catalyst solu-
tion containing about 57% by weight lith-
ium neodecanoate and about 43% by weight
diethylene glycol monobutyl ether and con-
tains about 2% by weight lithium.
______________________________________
EXAMPLE 1: Sole Catalysts
In this example, various catalysts were utilized alone with the base
composition of Component A. The metals in these catalysts were bismuth
(Bi), zinc (Zn), antimony (Sb) and lithium (Li).
As indicated in Table 3, the bismuth catalyst solution (Sample No. 1-1)
reacts and gels quite quickly and, as a result, flowability of the plywood
patch formulation is very poor.
As for the zinc-, antimony- and lithium-based catalysts, none of these
catalysts produced an acceptable plywood patch as measured by the
reactivity profile (Shore A hardness vs. time). An acceptable plywood
patching formulation would be one for which reaction and curing begin
within about 30.+-.3 seconds. At the catalyst levels of about 0.41 to 0.42
parts of catalysts or catalysts solution per 100 parts of the base
composition of Component A (pph) (Samples No. 1-2, 1-4 and 1-6), all three
catalyst types took well over 200 seconds for any reaction to occur, and
then only the lithium-based catalyst showed any promise with a final cure
hardness of 72 as measured by Shore A after 3000 seconds (50 minutes). The
antimony-based catalyst produced a foaming patch which did not cure and
remained tacky and spongy well past 3000 seconds. The zinc-based catalyst
likewise showed a very slow reaction with very little activity until about
1400 seconds. Additionally, the concentration of zinc-, antimony-, and
lithium-based catalyst or catalyst-solution used separately had to be
increased greatly to between 2.5 to 6.0 pph levels to get any type of
reaction to occur. These catalysts separately did not produce acceptable
patch formulations and at these concentration levels would be cost
prohibitive to use.
TABLE 3
__________________________________________________________________________
(Sole Catalyst)
__________________________________________________________________________
Sample No. 1-1 1-2 1-3 1-4 1-5 1-6 1-7
Catalyst Level.sup.a /Catalyst
0.26/A 0.42/B
2.5/B 0.42/C 2.5/C 0.41/D
6.0/D
Metal Bi Zn Zn Sb Sb Li Li
Moles of Metal
3.48 .times. 10-6
1.4 .times. 10.sup.-5
8.4 .times. 10.sup.-5
6 .times. 10.sup.-6
3.7 .times. 10.sup.-5
1.2 .times. 10.sup.-5
1.7 .times. 10.sup.-4
Flowability very poor
good good good excellent
good good
Gel Time (sec.)
14 none 380 none 50 180 80
Tack Free Time (sec.)
22 1300 450 2700 60 220 150
Shore A Hardness
80 sec. 48 none -- none 5 none --
100 sec. 50 none -- none 6 none --
120 sec. 53 none -- none -- none --
150 sec. 56 none -- none -- none --
175 sec. 58 none -- none (foam)
-- none --
200 sec. 62 none -- none 20 none --
250 sec. 68 none -- none -- 19 --
300 sec. 69 none -- none -- 28 28
400 sec. 72 none -- none 25 36 --
500 sec. 74 none -- none -- 45 --
600 sec. 76 none -- none -- 50 --
800 sec. -- none -- none -- 58 --
1000 sec. -- none -- none -- 60 --
1400 sec. -- 20 -- none -- -- --
2000 sec. -- -- -- none -- 68 --
2500 sec. -- 36 -- none -- 70 --
3000 sec. -- 42 20/15 min.
spongy 32/30 min.
72 40/30 min.
Adhesion Time (sec.)
556 2175 1800 none (foam)
none 2300 1800
Comments Sticky No Foam Foam No foam
__________________________________________________________________________
.sup.a parts catalyst or catalyst solution per 100 parts of base
composition of Component A.
"--" denotes test not performed.
EXAMPLE 2: Bismuth/Zinc Co-catalyst System
In this example, various ratios of bismuth-based catalyst to zinc-based
catalyst were utilized with the base composition of Component A. The
weight ratio of the bismuth-based catalyst solution to the zinc-based
catalyst ranged from about 20:80 to about 90:10 which corresponds to a
mole ratio range of bismuth to zinc metal of about 1:10 to about 1:0.25.
As indicated in Table 4, an acceptable plywood patch formulation was one
having a bismuth-based catalyst solution to zinc-based catalyst weight
ratio ranging from about 40:60 to about 70:30, which corresponds to a mole
ratio range of bismuth to zinc metal of about 1:3.8 to about 1:1.1. Above
about 70:30 weight ratio (mole ratio of bismuth to zinc of about 1:1.1),
the plywood patch formulation tends to gel too quickly for adequately
processing it through the mixing equipment. Whereas below the 40:60 weight
ratio (mole ratio of bismuth to zinc metal of about 1:3.8), the patch
formulation tack free time starts to become too slow for on-line
processing and could result in a soft patch which may cause boards to
stick together when stacked. Thus, to produce a most acceptable plywood
patch formulation utilizing a co-catalyst system using a bismuth-based
catalyst and a zinc-based catalyst, the bismuth and zinc metals therein
should be present such that the mole ratio of bismuth metal to zinc metal
is from about 1:4 to about 1:1.
TABLE 4
__________________________________________________________________________
(Bismuth/Zinc)
__________________________________________________________________________
Sample No. 2-1 2-2 2-3 2-4 2-5 2-6 2-7 2-8
Ratio A/B Catalyst
20/80 30/70 40/60 50/50 62.5/37.5
70/30 75/25 90/10
A Catalyst Level.sup.a
.084 .126 .168 .21 .26 .294 .315 .378
B Catalyst Level.sup.a
.336 .294 .252 .21 .15 .126 .105 .040
Moles of Metal:
Bi 1.1 .times. 10.sup.-6
1.7 .times. 10.sup.-6
2.25 .times. 10.sup.-6
2.8 .times. 10.sup.-6
3.48 .times. 10.sup.-6
3.9 .times. 10.sup.-6
4.2 .times. 10.sup.-6
5.1 .times.
10.sup.-6
Zn 1.13 .times. 10.sup.-5
9.9 .times. 10.sup.-6
8.5 .times. 10.sup.-6
7.1 .times. 10.sup.-6
5.05 .times. 10.sup.-6
4.24 .times. 10.sup.-6
3.5 .times. 10.sup.-6
1.3 .times.
10.sup.-6
Mole Ratio of
1:10 1:5.8 1:3.8 1:2.5 1:1.5 1:1.1 1:0.8 1:0.25
Bi:Zn
Flowability
Real good
good good good good good poor poor
Gel Time (sec.)
72 36 26 27 21 20 16 16
Tack Free Time (sec.)
92 56 42 44 28 34 25 23
Shore A Hardness
80 sec. -- 42 40 32 42 40 55 52
100 sec. 15 47 48 40 47 48 60 58
120 sec. 22 53 55 46 57 56 62 61
150 sec. 38 60 58 53 59 58 66 65
175 sec. 44 62 64 55 62 61 70 65
200 sec. 50 66 65 60 64 63 73 67
250 sec. 54 70 68 64 66 66 77 69
300 sec. 58 71 72 68 71 67 78 70
400 sec. 64 74 73 72 73 70 79 72
500 sec. 70 77 74 75 75 73 80 73
600 sec. 74 79 76 76 78 75 80 76
Adhesion Time (sec.)
165 95 90 110 240 180 160 155
Comments Tack free
Good Appears
Would be
Acceptable
Acceptable
Gels
Gels too
too slow
adhesion;
acceptable
acceptable but fast fast
tack free beginning
too slow to gel too
quickly
__________________________________________________________________________
.sup.a Parts of catalyst or catalyst solution per 100 parts of base
composition of component A.
EXAMPLE 3: Bismuth/Antimony Co-catalyst System
In this example, various ratios of bismuth-based catalyst to antimony-based
catalyst were utilized with the base composition of Component A. The
weight ratio of the bismuth-based catalyst solution to the antimony-based
catalyst solution ranged from about 25:75 to about 80:20, which
corresponds to a mole ratio range of bismuth to antimony metal of about
1:3.5 to about 1:0.3.
As indicated in Table 5, an acceptable plywood patch formulation is one
having a bismuth-based catalyst solution to antimony-based catalyst
solution ranging from about 50:50 to about 75:25, which corresponds to a
mole ratio range of bismuth to antimony of about 1:1.1 to about 1:0.4.
Below the 50:50 weight ratio (mole ratio of bismuth to antimony of 1:1.1),
the reaction tends to proceed too slowly to be processable at a rapid rate
and no adhesion occurred even after 30 minutes. Above the 75:25 weight
ratio (mole ratio of bismuth to antimony of 1:0.4), the reaction tends to
occur too fast for desired processability and did not achieve a good flow
into defect areas on the plywood board. Thus, to produce a most acceptable
plywood patch formulation utilizing a co-catalyst system using a
bismuth-based catalyst and an antimony-based catalyst, the bismuth and
antimony metals therein must be present such that the mole ratio of
bismuth metal to antimony metal is from about 1:1.1 to about 1:0.4.
TABLE 5
__________________________________________________________________________
(Bismuth/Antimony)
__________________________________________________________________________
Sample No. 3-1 3-2 3-3 3-4 3-5 3-6 3-7
Ratio A/C Catalyst
25/75 30/70 40/60 50/50 60/40 75/25 80/20
A Catalyst Level.sup.a
.085 .102 .136 .17 .204 .255 .27
C Catalyst Level.sup.a
.255 .238 .204 .17 .136 .085 .07
Moles of Metal:
Bi 1.1 .times. 10.sup.-6
1.4 .times. 10.sup.-6
1.8 .times. 10.sup.-6
2.3 .times. 10.sup.-6
2.7 .times. 10.sup.-6
3.4 .times. 10.sup.-6
3.6 .times. 10.sup.-6
Sb 3.8 .times. 10.sup.-6
3.5 .times. 10.sup.-6
3.0 .times. 10.sup.-6
2.5 .times. 10.sup.-6
2.0 .times. 10.sup.-6
1.26 .times. 10.sup.-6
1.04 .times. 10.sup.-6
Mole Ratio of
1:3.5 1:2.5 1:1.67
1:1.1 1:0.75
1:0.4 1:0.3
Bi:Sb
Flowability
good good excellent
good good good poor
Gel Time (sec.)
54 50 40 20 20 20 15
Tack Free Time (sec.)
105 80 66 38 32 33 24
Shore A Hardness
80 sec. -- -- 5 20 41 40 48
100 sec. -- 5 5 34 48 45 58
120 sec. 5 18 20 43 50 50 64
150 sec. 10 26 28 47 55 54 70
175 sec. 13 32 38 52 57 58 70
200 sec. 30 40 40 56 60 61 72
250 sec. 42 45 46 58 63 65 73
300 sec. 44 50 53 60 65 66 73
400 sec. 50 55 55 63 69 71 75
500 sec. 56 59 57 65 71 72 77
600 sec. 58 62 63 68 72 73 77
Adhesion Time (sec.)
none none 750+ 230 200 210 175
Comments Slow Slow, Soft and
Reacts
Reacts
Reacts Gels too
reacting.
sticky.
sticky.
ok. ok. ok. fast
Sticky.
No Slow Shore A =
No adhesion.
adhesion.
72 max.
adhesion.
__________________________________________________________________________
.sup.a Parts of catalyst or catalyst solution per 100 parts of base
composition of Component A.
EXAMPLE 4: Bismuth/Lithium Co-catalyst System
In this example, various ratios of bismuth-based catalyst to lithium-based
catalyst were utilized with the base composition of Component A. The
weight ratio of the bismuth-based catalyst solution to the lithium-based
catalyst ranged from about 25:75 to about 75:25, which corresponds to a
mole ratio range of bismuth to lithium metal of about 1:6.6 to about
1:0.7.
As indicated in Table 6, an acceptable plywood patch formulation was one
having a bismuth-based catalyst solution to lithium-based catalyst
solution ranging from about 25:75 to about 57:43, which corresponds to a
mole ratio range of bismuth to lithium metal of about 1:6.6 to about
1:1.65. At the 25:75 weight ratio, the adhesion of the reacted plywood
patch formulation to the plywood board tends to be too slow (about 10
minutes). This would require an extended cure of the plywood boards or
panels before they are processed further in a processing plant, which may
or may not be acceptable to some existing plant operations. Weight ratios
of 60:40 or higher produce fast reacting formulations which make it
difficult to process in plant operations and tend to affect flowability
into defect areas of the plywood board. Thus, to produce a most acceptable
plywood patch formulation utilizing a co-catalyst system using a
bismuth-based catalyst and a lithium-based catalyst, the bismuth and
lithium metal therein must be present such that the mole ratio of bismuth
metal to lithium metal is from about 1:6.6 to less than about 1:1.6 (i.e.
more lithium per mole of bismuth).
TABLE 6
__________________________________________________________________________
(Bismuth/Lithium)
__________________________________________________________________________
Sample No. 4-1 4-2 4-3 4-4 4-5 4-6
Ratio A/D Catalyst
25/75 40/60 50/50 57/43 60/40 75/25
A Catalyst Level.sup.a
.115 .184 .23 .26 .276 .345
D Catalyst Level.sup.a
.345 .276 .23 .20 .184 .115
Moles of Metal:
Bi 1.5 .times. 10.sup.-6
2.5 .times. 10.sup.-6
3.1 .times. 10.sup.-6
3.5 .times. 10.sup.-6
3.7 .times. 10.sup.-6
4.6 .times. 10.sup.-6
Li 9.9 .times. 10.sup.-6
7.96 .times. 10.sup.-6
6.6 .times. 10.sup.-6
5.8 .times. 10.sup.-6
5.3 .times. 10.sup.-6
3.3 .times. 10.sup.-6
Mole Ratio of
1:6.6 1:3.2 1:2.1 1:1.65
1:1.4 1:0.7
Bi:Li
Flowability
excellent
good fair excellent
poor poor
Gel Time (sec.)
33 20 20 22 16 16
Tack Free Time (sec.)
43 32 28 33 22 21
Shore A Hardness
80 sec. 42 48 50 40 50 49
100 sec. 48 54 56 48 58 60
120 sec. 55 59 60 52 64 63
150 sec. 56 63 64 56 65 66
175 sec. 58 65 66 60 67 68
200 sec. 61 65 69 63 70 70
250 sec. 64 68 70 65 72 71
300 sec. 66 70 72 66 73 73
400 sec. 70 72 73 70 74 75
500 sec. 73 74 74 71 75 78
600 sec. 75 76 78 73 75 81
Adhesion Time (sec.)
550 375 300 400 275 170
Comments Slow Acceptable
Would Rubbery
Gels too
Gels too
reactivity.
reactivity.
make fast. fast.
Slow Slow acceptable
adhesion.
adhesion.
patch.
__________________________________________________________________________
.sup.a Parts of catalyst or catalyst solution per 100 parts of base
composition of Component A.
The reaction product of isocyanates and polyols and other hydroxyl
containing compounds utilizing the co-catalyst system of the present
invention may be further utilized as elastomers, coatings, foundry resins,
adhesives, urethane-isocyanate sealants and caulkings, carpet backings and
any structural polymers which incorporate such reaction products.
It will be apparent from the foregoing that many other variations and
modifications may be made in the processes and the compositions
hereinbefore described, by those having experience in this technology,
without departing from the concept of the present invention. Accordingly,
it should be clearly understood that the processes and compositions
referred to in the foregoing description are illustrative only and are not
intended to have any limitations on the scope of the invention.
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